Information

Table 28-50. Read Once Command FCCOB Requirements (continued)
FCCOB Number FCCOB Contents [7:0]
Returned Values
4 Read Once byte 0 value
5 Read Once byte 1 value
6 Read Once byte 2 value
7 Read Once byte 3 value
After clearing CCIF to launch the Read Once command, a 4-byte Read Once record is
read from the program flash IFR and stored in the FCCOB register. The CCIF flag is set
after the Read Once operation completes. Valid record index values for the Read Once
command range from 0x00 to 0x0F. During execution of the Read Once command, any
attempt to read addresses within the program flash block containing this 64-byte field
returns invalid data. The Read Once command can be executed any number of times.
Table 28-51. Read Once Command Error Handling
Error Condition Error Bit
Command not available in current mode/security FSTAT[ACCERR]
An invalid record index is supplied FSTAT[ACCERR]
28.4.10.11 Program Once Command
The Program Once command enables programming to a reserved 64-byte field in the
program flash 0 IFR (see Program Flash IFR Map and Program Once Field). Access to
the Program Once field is via 16 records, each 4 bytes long. The Program Once field can
be read using the Read Once command (see Read Once Command) or using the Read
Resource command (see Read Resource Command). Each Program Once record can be
programmed only once since the program flash 0 IFR cannot be erased.
Table 28-52. Program Once Command FCCOB Requirements
FCCOB Number FCCOB Contents [7:0]
0 0x43 (PGMONCE)
1 Program Once record index (0x00 - 0x0F)
2 Not Used
3 Not Used
4 Program Once Byte 0 value
5 Program Once Byte 1 value
6 Program Once Byte 2 value
Table continues on the next page...
Chapter 28 Flash Memory Module (FTFL)
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 639